Convert Input to Request facade

Laravel 5.2 no longer registers the `Input` facade by default. While
still available in Laravel 5, the `Input` facade is removed in
Laravel 6.

config/app.php

@@ -214,7 +214,6 @@ return [
         'Event' => 'Illuminate\Support\Facades\Event',
         'File' => 'Illuminate\Support\Facades\File',
         'Hash' => 'Illuminate\Support\Facades\Hash',
-        'Input' => 'Illuminate\Support\Facades\Input',
         'Inspiring' => 'Illuminate\Foundation\Inspiring',
         'Lang' => 'Illuminate\Support\Facades\Lang',
         'Log' => 'Illuminate\Support\Facades\Log',